| abstract |
The invention concerns a process for preparing polytetrahydrofuran, copolymers of tetrahydrofuran and 2-butin-1,4-diol, diesters of these polymers with C2-C20 monocarboxylic acids or monoesters of these polymers with C1-C10 monocarboxylic acids by polymerizing tetrahydrofuran in the presence of one of the following telogens, water, 1,-4-butane diol, 2-butin-1,4-diol, polytetrahydrofuran with a molecular weight of between 200 and 700 Dalton, or of a C1-C10 monocarboxylic acid or a carboxylic acid anhydride produced from C2-C20 monocarboxylic acids or mixtures of these telogens on a heterogeneous carrier catalyst which contains a catalytically active amount of an oxygenous molybdenum and/or tungsten compound on an oxidic carrier material, and which has been calcined at temperatures of between 500 °C and 1000 °C after application of the precursor compounds of the oxygenous molybdenum and/or tungsten compounds to the carrier material precursors. Before it is used as a polymerization catalyst, the catalyst is activated by treatment with a reducing agent. |